detection and identification of toxoplasma gondii type one infection in sheep aborted fetuses in qazvin province of iran

background: the aim of this study was to apply the nested-pcr and bioassay methods in detection and genotyping of toxoplasma gondii infection in provided sheep aborted fetus samples from qazvin province of iran. methods : eighteen sheep aborted fetal samples were studied by nested-pcr-rflp, histopathologi­cal observation and microbiological assay. bioassay in mice was carried out by inoculating the brain samples intraperitoneally. results : the results demonstrated the frequency of 66% infected sheep aborted fetal samples with t. gondii type one. although we could not isolate any parasite from inoculated mice even after three pas­sages, but it was confirmed histopathologically formation of cyst like bodies in prepared mice brain sections. conclusion : the results of the performed nested-pcr and formation of brain cyst in inoculated mice exhibited that t. gondii type one infection might be considered as one of the major causative agents for abortion in ewes.